Compressor



Get. 18, 1949. q. H. STEENSTRUP I 2,485,417,

' COMPRESSOR Filed June 20, 1944 2 Carl H. Steenstr up,

His Attorney.

Patented Oct. 18, 1949 comnsson Carl B. Steenstmp, Schenectady. N. Y., asslgnor to General Electric Com New York many, a corporation of Application June 20, 1944, Serial No. 541,143

My invention relates to compressors and particularly to compressors for hermetically sealed refrigerating machines.

In the operation of hermetically sealed refrigerating machines it is the usual practice to provide a sump for maintaining a body of lubricant within the hermetically sealed casing containing the motor and compressor, the lubricant being circulated by a suitable pump to the moving parts of the mechanism. The hermetically sealed casing constitutes a chamber in the closed refrigerant circuit, the casing being filled with refrigerant gas. During those portions of the refrigerating cycle when the compressor is idle, there is a tendency under certain conditions of operation for the refrigerant gas to condense and for the liquid refrigerant to collect in the lubricant sump. When the refrigerating machine is started thereafter, liquid refrigerant is apt to be drawn into the oil pump; and, in those machines in which the hermetically sealed casing is on the low pressure side of the system, the liquid refrigerant in the lubricant sump will boil, and some of the gas bubbles may be drawn into the lubricant pump. The admission to the pump of refrigerant either as a liquid or a gas is undesirable .since it delays the supplying of adequate lubricant to the moving parts of the mechanism and also may result in undesirable noise during the operation of the machine. Another difliculty encountered in refrigerating'machines of this type is that a small amount of sediment or sludge is sometimes formed 9 Claims. (Cl- 230-206) which collects in the lubricant sump. For obvious reasons it is desirable to prevent the circulation of this foreign matter through the lubricating passages. I

Accordingly, it is an object of my invention to provide a compressor having a lubricant sump and a lubricant circulating ump and including an improved arrangement'for preventing the admission of foreign matter to the lubricant pump.

It is another object of my invention to provide a refrigerant compressor having a lubricant circulating system and an improved baflle construction for the intake of the lubricant pump to minimize the admission to the pump of foreign matter including gas bubbles and liquid other than the lubricant.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to the accompanying drawing in which Fig. 1 is a side elevation view partly in section of a closed refrigerant compressor embodying my invention; Fig. 2 is an end view partly in section of the compressor shown in Fig. 1; Fig. I

3 is an explodedperspective view of the oil intake baille of the compressor of Fig. 1; and Fig. 4 is a sectional view of the lubricant pump on the line 4-4 of Fig. 1.

Briefly, the compressor unit illustrated in the drawing comprises a motor and a reciprocating compressor mounted in a hermetically sealed casing, the compressor being arranged to draw refrigerant gas into the casing and to discharge high pressuregas to the refrigerant circuit outside the casing through a suitable exhaust conduit. The moving parts of the mechanism are supplied with oil or other suitable lubricating liquid by the operation of a pump which circulates oil from the sump in the bottom of the casing to the several moving parts of the mechanism. During some of the idle periods of operation, refrigerant may condense in the casing and fall into the sump, and a sheet metal'baflle is provided which includes an elongated horizontal opening having an area several times the size of the area of the oil pump intake so that the velocity of the lubricant stream at the elongated opening is low. The baflle is also formed to catch and deflect away from the opening any liquid refrigerant falling into the body of oil and is also provided with a bafllc deflecting away from the elongated opening any bubbles of gaseous refrigerant rising through the body of oil. The great reduction in the velocity of the oil entering the intake baflie minimizes the tendency to pick up sediment or other foreign matter in the body of oil and the baflle deflects away from the intake opening both liquid and gaseous refrigerant.

The arrangement of the baflie prevents undue noise and faulty lubrication of thecompressor.

Referring now to the drawing, the compressor shown in'Figs. 1 and 2 comprises a hermetically sealed'casing i formed by securing end plates 2 and 3 to a cylindrical shell 4 which also constitutes the frame of an electric driving motor having a stator 5 and a rotor B. A reciprocating compressor having a compressor block 1 is rigidly mounted within the shell 4 and includes a crank shaft 9 on which the rotor 6 is mounted. Within the compressor block is formed a cylinder l0 having a reciprocating piston ll mounted therein and'driven by a crank I! on the shaft 9. A body of oil or other suitable liquid lubricant is maintained in the bottom of the casing I which constitutes a lubricant sump, the oil being maintained at a normal level indicated at l3. Oil is circulated from the sump to the moving parts of the mechanism by operation of a pump indicated generally at M which draws the lubricant through a hollow baflle or vessel It arranged below the normal level l3. From the baflle IS the oil enters an intake passage l6 of the pump, flows to the pump and then is circulated through a series of passages in the compressor block and crank shaft to the moving parts of the mechanism, these passages, being within the block, are indicated for the most part by dotted lines on the drawing. In order to maintain the pressure of the lubricant at a predetermined value, a fluid pressure regulating piston i1 is provided on the discharge side of the pump, the pressure maintained by the piston ll, being determined by the calibration of a spring Ill.

The details of construction of the compressor, including the arrangement for mounting the crank shaft 9 and the construction of the piston and connecting rod assembly, are described and claimed in a copending application of Christian Steenstrup, Serial No. 541,145, filed concurrently herewith, now Patent No. 2,394,469.

The pump I as shown in Fig. 4 comprises an eccentric portion [3 of the shaft 9 and a spring-pressed vane 20 which rides on the surface of the portion l9. Oil from the passage 16 is circulated by the rotation of the eccentric l9 and is discharged through a passage 2| formed in the block 1 adjacent the shaft 9. The rotation of the shaft thus provides a continuous flow of lubricant; however, if liquid or gaseous refrigerant enters, the pump, noise may be produced and inadequate lubrication may result since compressors of this type are operated normally at relatively high speeds, say 1800 R. P. M. The baiiie I5 is provided in order to minimize or prevent the admission of refrigerant or other foreign matter to the pump. This baflie as shown in Figs. 1, 2 and 3 comprises upper and lower sheet metal portions of plates 22 and 23, respectively, providing a hollow vessel or chamber. The plate 23 is provided with an indentation 24 and the two plates are held together by outwardly extending flanges 25 formed on the plate 23. The flanges 25 engage the sides of an upwardly turned flange 26 which extends about the major portion of the periphery of the plate 22. 'A small downwardly extending projection 21 on the plate 22 holds the plates in spaced relation at their forward ends. When the baiile is placed in position on the compressor, screws 28 passing through holes 29 and 30 in the upper and lower plates, respectively, clamp the ends of the plates securely together against the compressor block at the pump intake IS, an opening surrounded by a boss 3| being provided in the upper plate 22 so that the chamber formed by the indentation 24 is in communication with the intake IS. The upturned flanges 25 on the plate 23 determine the length of the elongated opening formed between the two plates. This opening has an area substantially greater than the area of the intake It so that when lubricant is drawn into the chamber 24 by operation of the pump, the velocity of the lubricant at the elongated opening is substantially less than the velocity at the intake It. The relative sizes of the pump intake and the elongated opening may vary according to the design of the particular compressor; for example. it has been found that a baflle opening about three times the area of the pump intake gave satisfactory results in one compressor constructed as shown on the drawing. This reduction in velocity minimizes the possibility that sediment or sludge will be drawn from the bottom of the casing into the pump intake. The bailie I5 is arranged directly below the cylinder Ill. The elongated opening between the plates 22 and 23 indicated at 32 in Figs. 1 and 2 is spaced from the bottom of the sump and is directly below the outer bearing portion 33 of the compressor block. During idle periods of the compressor, refrigerant may condense on the sides of the block I and on the mechanism below the piston. The liquid refrigerant formed will drop from the block and fall into the liquid lubricant and thence some will fall onto the baffle [5. The opening 32 is located below the portion -33 of the block to minimize the possibility of liquid refrigerants falling directly toward the opening. Liquid refrigerant which does fall on the plate 22 is retained by the upturned flange 26 so that it does not flow into the opening 32, but instead flows away from the opening toward the bottom end of the baffie from which it flows to the bottom of the casing at the ends of the flange 26. When the compressor is started, liquid refrigerant in the oil is boiled by the reduction of the pressure in the casing and the refrigerant bubbles rising through the lubricant tend to be drawn into the opening 32; however, the plate 23 is provided with a bafile portion 34 extending from the lower edge of the opening 32 throughout the length of the opening so that the gas bubbles are deflected away from the opening. The plate 23 when secured in position on the block extends somewhat downwardly from the horizontal so that, if during the idle period of the machine liquid refrigerant should fall onto the baiile adjacent the opening 32, it will tend to flow down the slope of the baflle to the bottom of the sump. Thus there is further assurance that liquid refrigerant will not be drawn into the baffie. I

The bafile construction described above is ex-' tremely simple and easy to construct but at the,

same time effectively minimizes the admission of foreign substances to the lubricant pump. Noise due to drawing refrigerant into the pump is prevented and a steady supply of liquid lubricant is insured so that inadequate lubrication due to the circulation in the lubricating system of refrigerant is prevented and an adequate supply of liquid lubricant assured. Furthermore, the usual oil intake screen or strainer is not required.

While I have described a specific form of my invention in connection with a hermetically sealed refrigerating machine, other applications will readily be apparent to those skilled in the art. I do not, therefore, desire my-invention to be limited to the construction illustrated and described and I intend by theappended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a compressor for a refrigerating machine, means providing a sump for collecting liquid lubricant, means for pumping lubricant from said sump to' the moving parts of the compressor, the

operation of the machine being such that liquefled refrigerant gas tends to collect in the sump during idle periods in the operating cycle, and intake means arranged below the normal level of lubricant in said sump for preventing the admission of refrigerant to said pumping means, saidintake means comprising ahollow vessel in communication with the intake of said pumping means and having a horizontal elongated opening spaced from the bottom of said sump and below the normal level of lubricant in said sump, said vessel having an upper wall shaped to collect liquid refrigerant descending through thelubricant and to convey the liquid refrigerant in a direction away from said elongated opening.

' 2. In a compressor for a refrigerating machine, means providing a sump for collecting liquid lubricant, a pump having intake and discharge passages for supplying lubricant from said sump to the moving parts of the compressor, and intake means arranged below the normal level of lubricant in said sump for minimizing the admission of substances other than lubricant to said pumping means, said intake means comprising a closed hollow vessel having a first opening therein in communication with the intake passage of said pump, said hollow vessel having a horizontal elongated opening below the normal level of lubricant in said sump and spaced from the bottom of said sump and remote from said intake passage and from said first opening, said elongated opening having an area great with respect to the area of said intake passage whereby the velocity of lubricant flowing through said elongated opening is low with respect to the velocity of lubricant in said intake passage and the tendency to draw into said opening matter other than lubricant is minimized.

3. In a compressor for a refrigerating machine, means providing a sump for collecting liquid lubricant, a pump for supplying lubricant from a body of lubricant in said sump to the moving parts of the compressor, and means providing an intake chamber for said pump below the normal level of lubricant in said sump for preventing the admission of foreign matter to said pump, the chamber of said intake means comprising a substantially closed hollow vessel having a first opening for communicating with the intake of said pump and having an elongated opening above the bottom of said sump and of materially greater area than the area of said intake said elongated opening being remote from said intake and from said first opening whereby the velocity of lubricant flowing through said elongated opening is low with respect to the velocity of lubricant at the intake of said pump.

4. In a compressor for a refrigerating machine, means providing a sump for collecting a body of liquid lubricant, a pump for supplying lubricantfrom said body of lubricant to the moving parts of the compressor, an oil intake device for said pump providing a horizontally extending chamber below the level of liquid lubricant in said sump, said chamber communicating at one end with the intake of said pump and having a substantially horizontal elongated opening at its other end above the bottom of said sump and below the level of lubricant, and a baflle extending from the lower edge of said opening for minimizing the admission of gaseous refrigerant to said opening.

5. In a compressor for a refrigerating machine, means providing a sump for collecting liquid lubricant, a pump having intake and discharge passages for supplying lubricant from said sump to the moving parts of the compressor, the operation of the machine being such that liquefied refrigerant gas tends tov collect in the sump durmeans arranged below the normal level of lubricant in said sump. for minimizing the admission of refrigerant to said pump, said intake means comprising a hollow vessel in communication with the intake passage of said pump and having a horizontal elongated opening above the bottom of said sump and below the normal level of lubricant in said sump, the area of said elongated opening being great with respect to the area of the pump intake passage whereby the velocity of the lubricant in said opening is relatively low, and a downwardly sloping baille extending from said vessel near the lower edge of said elongated opening for conveying liquid refrigerant descending through the body of lubricant in said sump away from said opening and for deflecting away from said opening bubbles of gaseous refrigerant rising through said body of lubricant.

6. In a compressor for a refrigerating machine, means providing a sump for collecting liquid lubricant, a pump including an intake below the level of lubricant in said sump for supplying lubricant from said sump to the moving parts of said compressor, the operation of the" machine being such that liquefied refrigerant gas tends to collect in the sump during idle periods in the operating cycle, and intake means for said pump comprising a baffle providing a horizontally extending chamber below the level of lubricant in said sump for preventing the admission of refrigerant to said pump, said chamber communicating with said intake and having a horizontal elongated intake opening above the bottom of said sump and remote from said intake of said pump and below the normal level of lubricant in said sump whereby the velocity of lubricant at said opening is relatively low, said bafiie being constructed and arranged to catch and deflect away from said elongated opening liquid refrigerant descending through said body of lubricant.

7. In a compressor for a refrigerating machine, means providing a sump for collecting liquid lubricant, a pump having an intake below the level of'liquid lubricant in said sum'p for supplying Y lubricant to the moving parts of the compressor,

the operation of the machine being such that liquefied refrigerant gas tends to collect in the sump during idle periods in the operating cycle, and a hollow relatively flat sheet metal bafile providing a chamber below the level of lubricant in said sump and communicating with said intake for minimizing the admission of refrigerant to said intake, said bafile comprising two sheet metal portions at least one of which has an indentation forming the chamber in said baffle, said portions being spaced apart at their ends remote from said intake to provide an elongated intake opening having an area substantially greater than that of said intake.

8. In a compressor for a refrigerating machine,

' means providing a sump for collecting liquid lubricant, a pump having an intake below the level of liquid lubricant in said sump for supplying lubricant to the movingparts of the compressor, the operation of the machine being such that liquefied refrigerant gas tends to collect in the sump during idle periods in the operating cycle, a hollow intake baflie mounted in communication with thejntake of said pump for minimizing the admission of refrigerant to the intake, said baflle comprising top and bottom sheet metal portions, said bottom portion having an indentation, and said portions being secured together so that said indentation forms a chamber between said poring idle periods in the operating cycle, intake tions, said portions being held in spaced relation remote from said intake to provide an elongated horizontal intake opening to the chamber and said top portion having an upturned flange for preventing the flow to said elongated opening of liquid refrigerant which falls on top of said baflie..

9. In a compressor for a refrigerating machine, means providing a sump for collecting liquid lubricant, a pump having an intake below the level of liquid lubricant in said sump for supplying lubricant to the moving parts of the compressor, the operation of the machine being such that liquefied refrigerant gas tends to collect-in the sump during idle periods in the operating cycle, and a hollow intake baflie mounted in communication with the intake of said pump for minimizing the admission of refrigerant to said intake,

said bailie comprising top and bottom sheet metal portions clamped together adjacent said intake and supported remote from said intake to provide an elongated opening therebetween, said bottom portion having an indentation forming a chamber between said portions, said top portion having an upturned flange for deflecting away from said opening liquid refrigerant falling through the lubricant, said bottom portion havaway-from said opening gas bubbles rising through I the lubricant. t

- CARL H. STEENSTRUP.

REFERENCES CITED The following references are of record in the flie of this patent:

UNITED STATE PATENTS Number Name Date 1,765,289 Steenstrup June 1'7, 1930 1,840,045 McCormack Jan. 5, 1932 1,922,092 Hull M Aug. 15, 1933 2,038,176 Hull Apr. 21, 1936 2,065,350 1 Steenstrup Dec. 22, 1936 2,138,664 Money Nov. 29, 1938 2,204,814 Newell June 18, 1940 2,235,962 Hornady Mar. 25, 1941 2,280,296 Mantle Apr. 21, 1942 2,283,024 woliert May 12, 1942 2,312,596 Smith Mar. 2, 1943 Certificate of Correction Patent No. 2,485,417 October 18, 1949 CARL H. STEENSTRUP It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 20, after a, first occurrence, insert the word substantially;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice. Signed and sealed this 21st day of March, A. D. 1950.

THDMAS F. MURPHY,

Assistant Oommz'ssz'mzer of Patents. 

